1. Technical Field
The present invention relates to a liquid supply device, a liquid ejecting apparatus, and a liquid supplying method.
2. Related Art
In the past, there was known an ink jet printer (hereinafter, referred to as “a printer”) as a liquid ejecting apparatus for ejecting a liquid onto a target. The printer performs printing on a print medium as the target by ejecting ink (a liquid) supplied to a printing head (a liquid ejecting unit) through nozzles formed in the printing head. In recent years, as disclosed in JP-A-9-164698, for example, there has been suggested a printer in which a pump driven to pressurize and supply ink to a printing head from an ink cartridge is formed in an ink passage (a liquid supply passage) connecting an ink cartridge (a liquid supply source) to the printing head.
That is, in the printer disclosed in JP-A-9-164698, a pump chamber of the pump is provided in an ink passage. An ink introducing port for introducing the ink from the ink cartridge and an ink lead-out port for leading out the ink to the printing head are provided in the pump chamber. In addition, a part of the wall surface of the pump chamber is formed by a diaphragm. A spring urging the diaphragm in a direction in which the volume of the pump chamber is increased is provided in the pump chamber.
An actuator provided outside the pump chamber pressurizes the diaphragm against the urging force of the spring and displaces the diaphragm in a direction in which the volume of the pump chamber is decreased to supply the ink in the pump chamber from the ink lead-out port to the printing head. In addition, when the pressurizing of the actuator is released, the urging force of the spring displaces the diaphragm in the direction in which the volume of the pump chamber is increased to introduce the ink from the ink cartridge to the pump chamber through the ink introducing port.
In this printer, however, air may permeate into the ink passage due to the configuration of the printer when the ink cartridge is exchanged, for example, and thus bubbles may occur and remain in the pump chamber provided in the ink passage. Moreover, when the bubbles remain in the pump chamber, air flowing with the ink or air permeating through the wall surface may result in greatly increasing the bubbles. When these bubbles are present in the pump chamber, the bubbles absorb the variation of pressure caused by the displacement of the diaphragm. Therefore, the supply of the ink to the printing head may deteriorate. Furthermore, when the increased bubbles flow toward the printing head, a problem may occur in that a print quality deteriorates due to dot omission or the like.